Memories may be included in a variety of apparatuses, such as computers or other devices, including but not limited to portable memory devices, solid state drives, personal digital assistants, music players, cameras, phones, wireless devices, displays, chip sets, set top boxes, gaming systems, vehicles, and appliances. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), flash memory, and resistance variable memory, among others.
Memories, such as resistance variable memory devices, may be used as non-volatile memory for a wide range of electronic devices. Resistance variable memory devices may include, for example, phase change memory (PCM) or resistive memory, among others.
In some instances, it may be desirable to use PCM to implement random access memory. However, implementation in this manner is not seamless as read operations cannot be performed at a memory location undergoing a write operation and write operations may be relatively slower than write operations of conventional RAM. For example, PCMs may require additional time to manage and complete write operations, such as preparing data to be written to memory, suspending a write operation for a read access request, and monitoring progress of a write operation.
As a result of the limitations of using PCM as RAM replacement, operation of PCMs in memory systems may be restricted and/or require additional mechanisms for operation. For example, write and read operations may not be performed at any time on any memory location, and as a result, status registers must be regularly queried to determine whether a particular write operation has completed before another write operation is performed. Additionally, in some applications write operations are necessarily suspended for read operations and resumed upon completion of the read operation.